The broad objective is to find out what the fast and slow oculomotor subsystems can do to relate such oculomotor capacity to the perception of a clear and stable world. Eye movements and contrast sensitivity of human subjects will be measured when their heads are stabilized with a SRI Double Purkinje Image tracker and also with a novel renolving magnetic field sensor coil monitor that permits ninocular eye, head and torso rotations to be measured accurately when the subject is free to move naturally within a one meter sphere. A subject with abnormally high retinal image motion accompanying congenital nystagmus and old and new world monkeys will be studied as well as normal human beings. Longitudinal studies of preschool and 10-year old children will be continued. The proposed research is significant because it will bring oculomotor and visual research, both done primarily under artificial laboratory conditions, into a naturL situation in which ordinary bodily activities are permitted while visual function and oculomotor compensation are measured. This is a new direction of research provoked by our recent findings that oculomotor compensation, in itself, cannot explain how we see a clear and stable world. The research will be collaborative, involving scientists (viz. Collewijn, Dell'Osso, Kowler, J. Z. Levinson and Skavenski) with expertise in several complementary areas.